It has been shown in the literature that interferometers can be used as building blocks to synthesize any desired input-output relation in an optical system. This work is described in detail in application U.S. Ser. No. 14/092,565 by the present inventor entitled “Self-configuring linear component algorithm” (SCLA), filed on Nov. 27, 2013. However, this work assumed that the interferometers being used were capable of providing ideal (or nearly ideal) extinction ratios, where all (or nearly all) of the output power of the interferometer is in one of the two interferometer outputs when the interferometer phase is adjusted appropriately.
In practice, it is difficult to fabricate interferometers to provide ideal extinction ratios. For individual device applications of interferometers, trimming each device after it is fabricated to improve the extinction ratio has been performed. However, this process of individually trimming each device one by one is most undesirable for the SCLA application, where a large number of interferometers may be needed in a system. Individual trimming of each interferometer in such a system could easily be prohibitively expensive.
Accordingly, it would be an advance in the art to provide improved extinction ratios in interferometers, especially in a manner that easily scales to a large number of interferometers.